When in 1770, Sydney Parkinson drew his superb illustrations of Australian flora and fauna, working aboard Captain Cook's sailing ship, the Endeavour, there were only about 280 parts per million (ppm) of carbon dioxide in the atmosphere. Now that humans have burned smokestack and exhaust-fume fossil fuels for two centuries, CO2 concentrations have increased by a third, to 387ppm. By the end of this century, the concentrations could rise to anywhere between 535 to 983 ppm. No one knows the safe limit of rise, but anything over 450 ppm appears a seriously higher risk, with runaway temperatures possible. It would not take much: a 6 degree Celsius rise in temperatures could mean 95 per cent of all species on Earth would be gone. It's like we're driving through a red light, with our eyes closed, wishing oil prices were lower.

This Earth Century is like no other. We live with the damage done to our thin blue mantle covering the planet, a warming lens of atmosphere still heating up air, ice and sea. Changes in climate seem to be accelerating, far ahead of forecasts outlined in the 2007 Fourth Report of the UN Intergovernmental Panel on Climate Change (IPCC). Only a year since that well researched report, it's become apparent from fresh studies and fieldwork that global warming is dramatically melting summer Arctic sea ice faster than the waters can freeze back. Much earlier than expected, the summer ice cap is forecast to disappear altogether sometime between 2013 and 2040 - the first time in a million years.

Glaciers, Greenland and Antarctica are each being radically affected by climate change and, in turn, climate change is being accelerated by the changes. Sea level rises are likely to jump from the Fourth Report estimated maximum of 59 centimetres to 1.2 metres above current sea level. Add tidal surges and more frequent extreme weather events, and impacts on coastal cities around the world are expected. The Maldives Government now announces it is seeking land elsewhere, in case it becomes necessary to relocate its entire population. Australia is a possible destination.

This year in Accra, in Bonn, in Bangkok, there have been climate change talks focusing on meaningful action, preparatory to the world meeting in the Polish industrial centre of Poznan, from December 1-12, to help create a successor to the Kyoto Protocol. By the time the process moves to Copenhagen in 2009, the world must have worked out some genuine pathways to deal with massive industrialisation and wholesale atmospheric pollution.

Rethinking affluence is obligatory; cooperation is essential. As big as the environmental crisis is, living sustainably centres around people, and politics, the means to achieve change. Centre stage is the world's most energy consuming, militarised and ideologically deregulated empire, teetering in the balance. Only a short time ago, the United States was fast descending into Abu Ghraib barbarianism, military overstretch, and sub prime meltdowns.

Then a man whose father was born in Kenya and mother in Kansas got elected president in a landslide, and he promised to conscientiously serve and asked his electors to sacrifice. Instead of giving tax breaks to rich oil companies, he said he was going to help create green jobs and create the conditions for peace. He also wanted the ordinary citizen to be part of the biggest change in country and community since the New Deal of the 1930s.

Dare we hope? This Hawaiian-born, Indonesian-raised, blended-family man dares us back: yes-we-can. It won't be the technologies he employs, but this affirming slogan, "yes-we-can", most likely to go into the history books as his achievement, an easy equal to FDR's, "We have nothing to fear but fear itself," to move a sleeping country into wakefulness again.

While the richest nation the world has ever seen contemplates economic seizure, social transformation, and the drip-drip-drip of an Arctic ice cap, the Chinese have created an economic miracle and an environmental disaster. Their actions fluctuate between the two. Cities rise out of villages, but the 10 most polluted cities in the world are found there.

In response, last month's economic renewal package, the biggest in Chinese history, addresses waste and water pollution, and the impact of the American crisis. The Chinese government says it is committed to a national climate change program, undertaking to reduce energy intensity per unit of GDP by 20 per cent by 2013, while developing renewable and supposedly clean energy. They want easier access to the wealthier countries' intellectual property rights, too, to accelerate the change to a green economy.

But the world is changing, and even China, with all of its poverty, is part of a new realignment, with new responsibilities, and cannot ignore its own ecological disasters in its own country. Denmark's environment minister has called on China to cut down on its emissions, saying recently, "Mali is not China and Somalia is not Saudi Arabia." Her point, I suppose, is that the once-developing world is less a single place, but more a mosaic, comprising the starving, the enriched, the civil war-torn and the superpower-on-the-rise. This is a world very new to us, fascinating and urgent, requiring a globalised consciousness.

We can wish the Poznan UN Climate Change Conference every success. It is worth thinking collectively how we can transform economic implosion into green transformation, and turn the mistakes of profligacy into the achievement of the Millennium Development Goals of enough water, food, good health, education and rights for every human on the planet. But the process is on a scale well beyond the reach of any one citizen. We can hold the intention, but equally it is not skilful to become overwhelmed by the enormity of the task, to shrink back into a withering complacency or shrug because we cannot imagine what is needed.

Sydney Parkinson showed the rest of the world a hint of the beauty of Australia's part of Creation.

Another Quaker, 20th century British playwright Christopher Fry, in "A Sleep of Prisoners", goes beyond an appreciation of beauty to question how we can face an extraordinary challenge. For him, in taking the longest stride, gratitude is our only strength: "Thank God our time is now when wrong comes up to face us everywhere!" Instead of cowering under its weight, the task, as big as it is, is "soul-sized", the enormous enterprise an opportunity amounting to "exploration into God".

These words, "soul" and "God", are not everyone's. They are some people's best guess at a mystery too hard to explain. But at the heart of Christopher Fry's verse is for each of us to find in what is all around us the task that has our name on it.

The Earth Century is not only about extraordinary people, though, as the 44th American president demonstrates, we may well find them as part of the overall work. But crucially this century will be about all the rest of us seeking out our own destiny, to discern and to be led by that destiny. Outer leadership that doesn't take anything away from anyone else, but gives to all; inner leadership that encounters ego, and turns it into service; meets affluence, and turns it into sufficiency; builds individuality, while working within a cooperative practice.

Such enormous challenges: environmental, financial and social. But thank God our time is now.